The yellow alert has been issued by the UK Health Security Agency (UKHSA).
It means that a forecast spell of cold weather could have significant impacts on health and social care services.
There could be a rise in demand for health services and deaths, particularly among over-65s and those with health conditions.
A map of the alerts currently in place (Image: UKHSA)
The alert came into force at 8pm on Sunday, December 28, and will remain in place until midday on January 5.
According to the Met Office, the temperature will sit between 3C and 6C in Norfolk for most of this week – although there will be lows of 1C overnight.
It will mostly be dry, apart from the odd shower, and the coast will be particularly blustery on Wednesday.
From January 2 to 11, “wintry showers” – including snow – will start to move south of Scotland.